The invention relates to a method and device for gas metal arc welding, wherein a current-carrying wire electrode is melted by an arc, and wherein gas metal arc welding is performed using a filler metal, which contains at least one constituent that releases deleterious emissions through evaporation.
Gas metal arc welding (GMA welding) involves an arc welding method that is used for the overlay welding, welding or soldering of one, two or more work pieces made out of metal materials. In an inert gas atmosphere, a wire electrode is here continuously fed in the form of a wire or belt and melted by an arc that burns between the work piece and wire electrode. The work piece here serves as a second electrode. In particular, the work piece here serves as a cathode, and the wire electrode as an anode. The cathode effects here at least partially melt the work piece, and form the molten bath. The end of the wire electrode is melted, and predominantly the arc yields a molten drop. Various forces cause the drop to detach from the wire electrode, and pass over into the molten bath. This process of melting the wire electrode, forming the drop, detaching the drop and having the drop interact with the work piece is referred to as material transfer.
In GMA welding, the wire electrode serves not only as an arc carrier, but also as a filler metal. When GMA welding alloys, the wire electrode contains a filler metal, which in turn contains special constituents. Melting the wire electrode also melts the filler metal, and hence these constituents, which then pass over into the molten bath. For example, special constituents like these can be used for welding high-alloy steels with chromium constituents.
However, melting the constituents can also cause the constituents to evaporate. Evaporating the constituents releases extremely deleterious emissions, which in particular are toxic and/or carcinogenic. The welder can at least partially breathe in these emissions, which poses a proven significant health risk. In order to reduce the loads and health risk for the welder, breathing masks can be used, and the emissions can be partially aspirated with suction burners. However, suction burners are associated with major disadvantages. Suction burners have a more cumbersome design and a greatly restricted accessibility. Moreover, they are much harder to handle by the welder. Furthermore, the extremely fine emission particles can often not be kept out by basic filters. In addition to that, the emissions most frequently empty out close to the material surface, and are difficult, if not impossible, to detect with the suction burner.
Therefore, the object of the invention is to reduce deleterious emissions, and hence the health risk posed to the welder, during the GMA welding of alloys.